1. Field of the Invention
The present invention relates generally to bridge plugs, and more particularly, but not by way of limitation, to a retrievable bridge plug suitable for setting inside the bore of a string of drill pipe to aid in the control of a well that is flowing out of control.
2. Description of the Prior Art
Bridge plugs are packing devices which are generally used to completely seal the bore of a string of pipe. Most commonly, bridge plugs are utilized to block the bore of a string of casing in a well.
Bridge plugs are typically set by engaging the bore of the pipe string with a set of slips and then mechanically or hydraulically setting a packer against the bore.
During the drilling of a well, a string of drill pipe with the drill bit connected to the lower end thereof extends down into a well bore and is rotated to extend the depth of the well bore.
If the drilling operator loses control of the fluids in the well bore, i.e., a blowout occurs, the well will initially be brought under control by shearing the drill pipe near the surface with the shear rams, and removing the upper portion of drill pipe and closing in the well above the sheared off upper end of the drill pipe. Well fluids may continue to flow upward through the drill pipe and through the well bore, which outward flow up through the well is controlled through the choke line.
In order to bring the well back under control, it is necessary at some point to remove the damaged upper portion of the drill pipe and reconnect new drill pipe segments thereto.
Accordingly, it is desirable to have a bridge plug which could be set in drill pipe to stop the flow up through the drill pipe so that the damaged upper portions of the drill pipe could be removed and replaced with new drill pipe segments.